U.S. Pat. No. 4,846,931 to Gmitter et al discloses a method for selectively removing an epitaxial film from a single crystal substrate upon which it was grown. The method comprises the steps of selectively etching away a thin release layer positioned between the film and the substrate and causing the edges of the film to curl upwardly as the release layer is etched away. This enchances an outdiffusion of reaction products of the etching process from the active etching area. A solution of support layer material is sprayed on the epitaxial film layer.
U.S. Pat. No. 4,686,001 to Okazaki discloses a method for producing a semiconductor light emitting device that includes a step of removing an InP cover layer by a selective etching process. The InP cover layer on an InGaAs contact layer may be selectively removed by an etching process using HCl or HBr as an etchant so that the previously formed contact layer is exposed.